It has long been a feature of many types of compositions, including cosmetic compositions, that they comprise a fragrance oil for the purpose of delivering a pleasant smell. This can improve the overall consumer acceptance of the composition or mask unpleasant odours. In fact, it can be the sole purpose of some compositions to impart a pleasant odour to suitable substrates including the skin and or hair.
Fragrance oils used within such compositions usually comprise many different perfume raw materials. Each perfume raw material used differs from another by several important properties including individual character, and volatility. By bearing in mind these different properties, and others, the perfume raw material can be blended to develop a fragrance oil with an overall specific character profile. To date, characters are designed to alter and develop with time as the different perfume raw materials evaporate from the substrate and are detected by the user. For example perfume raw materials which have a high volatility and low substantivity are commonly used to give an initial burst of characters such as light, fresh, fruity, citrus, green or delicate floral to the fragrance oil which are detected soon after application. Such materials are commonly referred to in the field of fragrances as “top notes”. By way of a contrast, the less volatile, and more substantive, perfume raw materials are typically used to give characters such as musk, sweet, balsamic, spicy, woody or heavy floral to the fragrance oil which, although may also be detected soon after application, also last for longer. These materials are commonly referred to as “middle notes” or “base notes”. Highly skilled perfumers are usually employed to carefully blend perfume raw materials so that the resultant fragrance oils have the desired overall fragrance character profile. The desired overall character is dependent both upon the type of composition in which the fragrance oil will finally be used and also the consumer preference for a fragrance.
In addition to the volatility, another important characteristic of a perfume raw material is its olfactory detection level, otherwise known as the odour detection threshold. If a perfume raw material has a low odour detection threshold, otherwise known as “high odour impact”, only very low levels are required of the raw material within a composition for it to be detected by the user, sometimes as low as a few parts per billion. Conversely, if a perfume raw material has a high odour detection threshold, otherwise known as a “low odour impact”, larger amounts of that material are required before it can be smelt by the user. To date, when developing a fragrance oil, it has been important to balance the fragrance with both low and high odour impact perfume raw materials since the use of too many high odour impact materials could lead to a short lived overwhelming scent. As such the levels of high odour impact perfume raw materials within a fragrance oil have traditionally been restricted.
To date, due to the physical characteristics of the perfume raw materials, ie the volatility and the odour detection impact, the possible types of overall characters of fragrances have been limited. In addition, it has been difficult to develop a fragrance oil which remains detectable on the substrate over very long periods of time. Furthermore, it has not always been possible to develop a fragrance character which retains its initial fragrance character over time. However, it is known that consumer preference for fragranced compositions is mostly driven by the initial character detected after application. It is therefore desirable to have a fragrance which retains its initial character over time, and wherein that character remains noticeable to the consumer over time. Since materials with high odour impact can be detected when only very small levels are present, they are particularly useful for developing a noticeable long lasting fragrance character. It is also desirable to be able to create new to the world fragrance character profiles wherein one, or several, well recognised characters, regardless of their volatility, are maintained overtime such that a unique long lasting, “top, middle and base note” character is created. As such, it would be advantageous to be able to create a fragrance oil which will impart, in a new way, fragrance materials with a high odour impact, such that they can be experienced both initially, and over a substantial period of time, by the user.
In the past, many attempts have been made to delay the volatility profiles of fragrance oils within many types of compositions to extend the overall fragrance effect. For instance the fragrance oil may be formulated to include a higher proportion of perfume raw materials with a low volatility and which are therefore more substantive on the substrate. However, as discussed above, this restricts the fragrance character that can be achieved over time. Another approach has been to chemically, and reversibly, modify the perfume raw materials to a pro-perfume compound which is disclosed in patent applications WO 98/47477; WO 99/43667; WO 98/07405; WO 98/47478; all of which are incorporated herein by reference. The resultant pro-perfumes are not themselves volatile but, after the chemical modification is reversed, usually by hydrolysis upon application to the substrate, the perfume raw material is released and can then evaporate in the usual way. In these examples the release rate of the perfume raw materials is controlled by the reaction rate of the pro-perfume to perfume raw material transformation.
Further disclosures have discussed improving the overall longevity of a fragrance by delaying the evaporation of the fragrance oils. A wide variety of techniques have been disclosed among them encapsulation of the perfume raw materials for example within capsules (disclosed in JP-A-58/052211, EP-A-303,461), absorbing the materials to a surface for example by using carbon or zeolites (disclosed in U.S. Pat. No. 6,033,679), occluding the release of the perfume raw materials for example by the formation of a film (disclosed in U.S. Pat. No. 3,939,099) and complexing the perfume raw materials for example by using cyclic oligosaccharides. The prior art on this latter method includes JP-A-6/287127 and JP-A-8/176587 which disclose use of hydroxyalkylated cyclodextrins within cosmetic compositions to sustain the effect of the fragrance; and JP-A-8/183719 and JP-A-10/120541 which discloses a combination of cyclodextrin encapsulated fragrance and non encapsulated fragrance within a deodorant composition for prolonging the fragrance duration to at least 2 hours, all of which are incorporated herein by reference.
Whilst the compositions and disclosures of the prior art provide useful teachings for prolonging the overall fragrance character of different compositions the approaches still have limitations. The pro-perfume approach is limited by those chemical modifications that can suitably be made to the perfume raw materials. In addition, the prior art is restricted by pro chemistries used, or by the use of low levels of pro perfumes, thus preventing the development of a fragrance oil which exhibits a broad range of top note characters over time. On the other hand, entrapment materials, when used in the traditional way, interact with a broad range of perfume materials including top, middle and base notes prolonging the overall character of the whole fragrance. As such the prior art does not sufficiently teach how to preferentially delay the evaporation of a large range of high odour impact perfume raw materials within a single fragranced composition such that these distinct characters can be recognised throughout the usage period. In addition, since, in general, entrapment such as that described suppresses the evaporation of only a relatively small amount of the perfume raw materials, the low level of delayed release is often not noticeable to the user. As such the prior art does not adequately teach how to provide a fragrance wherein the prolonged character has sufficient strength to be noticeable and remains distinctive over time.
Surprisingly, it has now been found that compositions comprising a fragrance oil and a material which is able to delay the evaporation of the fragrance oil, wherein the fragrance oil is blended to comprise low levels of “top note” perfume raw materials and wherein the weight ratio of “high odour impact” perfume raw materials which have an odour detection threshold of less than, or equal to, 50 parts per billion to entrapment material within the associated form falls in the range of 1:20 to 20:1, can be used to create a long lasting fragrance character profile which has prolonged, and noticeable distinct characters. In addition, it has been found that within such fragrance oils, much higher levels of “high odour impact” perfume raw materials can be used than would be acceptable in a traditionally developed fragrance which leads to new and distinct fragrance characters. Furthermore, this use of high levels of “high odour impact” perfume raw materials can result in a reduction in the level of fragrance oil that is required in the final finished product which can reduce skin sensitisation and can have cost reduction benefits both for the manufacturer and the consumer. By controlling the weight ratio between the entrapment material and the “high odour impact” perfume raw materials highly efficient use is made of the entrapment material which can also lead to a reduction in the amount of both fragrance oil and entrapment material required in any given formulation. In addition, this use of “high odour impact” perfume raw materials can also result in a reduction in the level of entrapment material required to achieve the desired benefit which can have both aesthetic benefits for the final formulation in addition to further cost saving benefits.
While not wishing to be bound by theory, it is believed that when the entrapment material is reversibly associated to the perfume raw materials that the compositions of the present invention are substantially free of fragrance—entrapment material complexes until applied to the substrate. Upon application the volatile solvent evaporates providing an initial fragrance burst while the remaining fragrance complexes with the entrapment material. Over time, this association breaks down resulting in release of the perfume raw materials. Since the composition comprises a fragrance oil which has been developed with a high level of “high odour impact” perfume raw materials, the very low levels of materials that are released from the association over time are easily detected by the user. In addition, despite the fact that the fragrance oil is developed with very high levels of “high odour impact” perfume raw materials, the association that forms means that the fragrance is not overwhelming when it is first applied.
In addition, because the volatilisation rate of any given ingredient has, until now, been mainly related to its own boiling point, it has not been possible to obtain recurring and intermittent blooms (or pulses) of specific fragrance characters throughout the complete usage period. Surprisingly it has now been found that, once a substrate has been fragranced using a composition of the present invention, the fragrance can be refreshed over time, either naturally or deliberately, to release periodic and unexpected blooms of one or several fragrance characters. Whilst not wishing to be bound by theory, it is believed that this can be achieved by enhancing the natural decomposition rate of the fragrance oil entrapment material association for example by application of water, either naturally by breathing on the complex or by sweating, or artificially by spraying on a mist and the like. This “activation” results in the user experiencing a noticeable bloom of fragrance character. Surprisingly it has been found that it is possible to “activate” this complex, and thus generate fragrance blooms, several times during the wear. It is also believed that the negative consumer perception of becoming used to a scent can be minimised or prevented as a result of periodic “activation” resulting in an unexpected perceptible altering in the overall character of the fragrance.
It is an object of the present invention to provide compositions, which impart a long lasting and noticeable fragrance character to the substrate on which they are applied. It is a further object of this invention to provide a fragrance which maintains its initial character profile over time in a noticeable way. This, and other objects of this invention, will become apparent in light of the following disclosure.